/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification of Java bytecode.
 *
 * Copyright (c) 2002-2018 GuardSquare NV
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.optimize.evaluation;

import proguard.classfile.*;
import proguard.classfile.constant.RefConstant;
import proguard.evaluation.BasicInvocationUnit;
import proguard.evaluation.value.*;

/**
 * This InvocationUnit loads parameter values and return values that were previously stored with the methods that are
 * invoked.
 *
 * @see StoringInvocationUnit
 * @author Eric Lafortune
 */
public class LoadingInvocationUnit extends BasicInvocationUnit {
    private final boolean loadFieldValues;
    private final boolean loadMethodParameterValues;
    private final boolean loadMethodReturnValues;

    /**
     * Creates a new LoadingInvocationUnit with the given value factory.
     */
    public LoadingInvocationUnit(ValueFactory valueFactory) {
        this(valueFactory, true, true, true);
    }

    /**
     * Creates a new LoadingInvocationUnit with the given value factory, for loading the specified values.
     */
    public LoadingInvocationUnit(ValueFactory valueFactory, boolean loadFieldValues, boolean loadMethodParameterValues,
        boolean loadMethodReturnValues) {
        super(valueFactory);

        this.loadFieldValues = loadFieldValues;
        this.loadMethodParameterValues = loadMethodParameterValues;
        this.loadMethodReturnValues = loadMethodReturnValues;
    }

    // Implementations for BasicInvocationUnit.

    public Value getFieldClassValue(Clazz clazz, RefConstant refConstant, String type) {
        if (loadFieldValues) {
            // Do we know this field?
            Member referencedMember = refConstant.referencedMember;
            if (referencedMember != null) {
                // Retrieve the stored field class value.
                ReferenceValue value = StoringInvocationUnit.getFieldClassValue((Field)referencedMember);
                if (value != null) {
                    return value;
                }
            }
        }

        return super.getFieldClassValue(clazz, refConstant, type);
    }

    public Value getFieldValue(Clazz clazz, RefConstant refConstant, String type) {
        if (loadFieldValues) {
            // Do we know this field?
            Member referencedMember = refConstant.referencedMember;
            if (referencedMember != null) {
                // Retrieve the stored field value.
                Value value = StoringInvocationUnit.getFieldValue((Field)referencedMember);
                if (value != null) {
                    return value;
                }
            }
        }

        return super.getFieldValue(clazz, refConstant, type);
    }

    public Value getMethodParameterValue(Clazz clazz, Method method, int parameterIndex, String type,
        Clazz referencedClass) {
        if (loadMethodParameterValues) {
            // Retrieve the stored method parameter value.
            Value value = StoringInvocationUnit.getMethodParameterValue(method, parameterIndex);
            if (value != null) {
                return value;
            }
        }

        return super.getMethodParameterValue(clazz, method, parameterIndex, type, referencedClass);
    }

    public Value getMethodReturnValue(Clazz clazz, RefConstant refConstant, String type) {
        if (loadMethodReturnValues) {
            // Do we know this method?
            Member referencedMember = refConstant.referencedMember;
            if (referencedMember != null) {
                // Retrieve the stored method return value.
                Value value = StoringInvocationUnit.getMethodReturnValue((Method)referencedMember);
                if (value != null) {
                    return value;
                }
            }
        }

        return super.getMethodReturnValue(clazz, refConstant, type);
    }
}
